Conventionally, an inkjet printer is known that is provided with an inkjet head that performs printing using ink along a main scanning direction on a print medium by moving in the main scanning direction, a platen which is provided with a printing portion supporting region extending in the main scanning direction and which is configured to be capable of supporting a portion of the print medium being printed by the inkjet head from an opposite side of the inkjet head, and a heater that extends in the main scanning direction and heats the printing portion supporting region of the platen (for example, see Patent Literature 1).